#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;

int height[26];
char word[11];

int scanInt()
{
    int n=0, ch = getchar_unlocked();
    while(ch<'0' || ch>'9')
    ch=getchar_unlocked();
    while(ch>='0' && ch<='9')
    {
        n= (n<<3) + (n<<1) + ch - '0';
        ch=getchar_unlocked();
    }
    return n;
}


int main(){
    int i,maxH;
    for(i=0;i<26;++i)
    {
        height[i]=scanInt();
    }
    scanf("%s",word);
    maxH=-1;
    for(i=0;word[i]!='\0';++i)
    {
        if(height[word[i]-'a']>maxH)
            maxH=height[word[i]-'a'];
    }
    printf("%d",maxH*(i));
    return 0;    
}